1. Field of the Invention
The present invention relates generally to a data receiving-processing apparatus, a data receiving-processing method and a broadcasting method, and more particularly to those adapted for use in transmitting and receiving digitized video data via a broadcast satellite or a communication satellite for example.
2. Description of the Related Art
There is recently noticed the remarkable diffusion of a broadcasting system which digitizes audio and video signals and broadcasts such signals via a satellite. Digitizing the desired signals permits transmission of data as well as video and audio signals.
According to this system, a broadcast signal can be received by the use of an exclusive data receiving-processing apparatus (decoder). This is rendered possible, by allocating a unique number (decoder ID) to each decoder and identifying such decoder ID, and providing a predetermined service (e.g., enabling reception of a particular pay program) only to a user having a specific decoder. In other words, it becomes possible to realize a conditional access function.
In this field, continuous growth is currently in progress for what services are providable, and a high possibility exists that new services in some novel form will start hereinafter. For this reason, it is preferred that each decoder be designed to be capable of receiving any new service upon start thereof. In a situation where a new service is receivable only by a user who has purchased a new decoder, there arises a difference among services capable of being received depending on the time of purchase of the decoder.
In the case of adding a new service (new function) as mentioned above, some additional modification needs to be given to the program in the decoder. In an attempt to achieve such modification, it has been discussed heretofore to adopt a method of collecting the decoder from each user and, after replacing the program ROM incorporated therein, returning the decoder to the user again or replacing the whole decoder with a new one, or to adopt a method of distributing a new IC card to each user and loading a new program from the IC card into the decoder by utilizing an IC card interface incorporated in the decoder.
However, in the situation where the number of decoders already sold amounts to a great number, as a practical matter, it would be difficult to collect all of the decoders. And in the method of distributing IC cards, there exists a problem that, in addition to the required cost, any modifiable program is limited to a short program since the memory capacity of the IC card is generally extremely small.